The invention pertains to a fuel-injection system for mixture-compressing combustion-engines employing external ignition and operating with continuous fuel injection into the induction tube. Deployed successively in the induction tube are a metering-member and an arbitrarily operable throttle-flap. The metering-member is actuated against a restoring-force in compliance with the air-flow rate, thereby positioning a control-slide serving as the moving part of a metering valve situated in the fuel-supply-line, to allocate a fuel-quantity in proportion to the air-quantity. The restoring-force is generated by fluid pressure acting on the control-slide.
Fuel-injection systems of this type have the purpose of providing, automatically, a favorable fuel-air mixture for all the operating requirements of the combustion engine, in order that complete combustion of the fuel shall occur, so that, while the output of the combustion engine is being maximized, and the fuel consumption minimized, the production of poisonous exhaust gases is prevented or, at the least, greatly reduced. The fuel quantity must therefore be precisely allocated according to the demands of all the operating conditions of the combustion engine, and the ratio of the air quantity to the fuel quantity must be changed as a function of the known operating variables, such as, for example, revolutions per unit time, load, temperature, and the chemical composition of the exhaust gases.
In familiar fuel-injection systems of this type, the fuel quantity is allocated in a preferably direct proportion to the air quantity flowing through the induction tube and the relationship between the allocated fuel quantity and the air quantity is changeable by changing the restoring force on the metering member as a function of known operating variables of the combustion engine, through an electro-magnetically actuated pressure-regulating valve.